Well, this is a first. Usually I record guitar through an amp, but client wants to try using one of the guitar emulations in Sonar for recording tomorrow (if you are in USA your tonight.) Two questions.
1. What is the best native one in the X series (I have 1-3).
2. Can you record with it without the latency lag? I am running ASIO drivers at 256 I think--is that 2.8ms? (I'm out.) I can go to 128 probably.
Any success stories?
Thanks. It's a first for me.

There was a post on this same subject in the "software" thread I think. There was Youtube video showing a shootout between TH2 and Guitar Rig. They were very similar But to my ears TH2 had a little more mid to high range bite, whereas Guitar Rig had more bottom end grunt. Having said that you could probably just change the patches to suit your requirements. Not sure about latency issues, better minds than mine to answer that one I think.

Thank you rebel. For anyone who is about to post I know I should bypass all other plugs before trying, and should probably even try it b4 wasting your time, but I just got the message from client, I'm out, and can't experiment--coupled with the fact there are probably people who record like this all the time. Next ? you might ask is what genre? I have a feeling we will going for a clean strat type sound (reverb/chorus/clean distortion). I have no problem finding the sound, main issue is latency. I've never recorded with input monitoring.

     I'll sometimes use a direct box to send a clean signal to Sonar and also to a real amp.
 This way you can hear the amp while tracking to ellimanate any latency problem but still record a clean signal to use with the amp sim.
     That being said, with other latency causing plugins frozen or disabled you should be able to monitor through the amp sim without any problem. 
   

I would suggest recording the clean signal (use a DI with a "thru" feed) while playing through stomp boxes or a racked effects unit. You could record that signal as well as it never hurts to blend it in later if needed. This way, you can ignore any lag while recording and then add the guitar/amp sim later.
 
Regards,
Dan
 

You can't get to 0 latency if you're playing through the amp sim in real time, but a few milliseconds should be low enough.  The recommendation of playing direct, monitor through a stompbox, but record the direct signal is good.  The trick when recording direct (with or without an amp sim) is to have the correct impedance.  Guitars are high impedance, so you want to plug into an interface that is designed for it.
 
The TH2 amp sim is good.  I can't recall if X1 came with Guitar Rig.  I use Guitar Rig (full version).  The lite version that came with SONAR for a while has a model of a Fender Twin Reverb.  That works great for Strat sounds.
 
Jim